1. Field of the Invention
The present invention relates to a system for displaying images, and more particularly, to an image display system having a light pen to input information.
2. Description of the Related Art
Generally, conventional image display devices have such a data interface function that electrical data provided from an image data processing device is converted into images. In the conventional image display devices, the electrical data from the image data processing device is externally inputted using various input devices, such as a keyboard, a key pad, a mouse, etc.
Recently developed display devices have a screen which is capable of receiving input data, and the input data is processed to display the processed data on the screen. In other words, a display device and an input device are unified in such display devices.
To configure a display system having the unified display device and the input device, the display device includes a touch screen panel. When a specific position on the touch screen panel is compressed, location information of the specific position is transferred to an information processing device. Then, the information processing device processes the location information to output a new image signal. The display device then displays a new image using the new image signal.
However, the touch screen panel increases weight and volume of the display device. Further, when an image or a picture to be displayed on the touch screen is minute, the touch screen panel is inappropriate.
More recently, there have been developments of display devices having capability of sensing light provided form an external input device to detect the location in which the light is entered into a display device. Such display devices have a light detect sensor, which detects the entered light and outputs a signal containing location information, as well as pixels for displaying images. The signal is transferred to the information processing device which then processes the signal to display image(s) corresponding to the location information.
Generally, a light pen is used to generate the light to be inputted onto the display device. The light pen includes a light source generating light of high luminance. A light emitting diode is generally used for the light source. The light emitting diode is disposed at an end portion of the light pen.
In such conventional display systems, the light pen generates white light which is then filtered by a color filter to form a single colored light. Such process decreases the amount of the light. Additionally, the single colored light passes through a liquid crystal layer, an indium tin oxide layer (or indium zinc oxide layer), an organic layer, etc. Thus, the amount of the light is more decreased. As a result, the light detect sensor may malfunction due to the decrease in the amount of the light provided to the light detect sensor. Further, the light pen includes the light source, such as a light emitting diode, to generate the light, it is inevitable to cause an increase in its weight and volume and manufacturing cost.
Therefore, a need exists for an image display system in which the amount light provided from a light pen is not or little decreased so that the light detect sensor operates properly and accurately. Further, it will be advantageous to provide an image display system in which the light detect sensor is disposed within a display panel of the display system so that there is no need of a touch screen panel. It is also further desirable to provide a light pen for the display system which provides light to the light detect sensor without a light source.